1. Field of the Invention
The present invention generally relates to an intersection warning system, and more particularly to an intersection warning system supplying, to an driver of a vehicle straightly passing through an intersection or turning at the intersection, information about another vehicle in a dead angle area of the driver, and warning based on the relationship between the vehicle and the other vehicle in the dead angle area.
2. Description of the Related Art
Conventionally, a vehicle collision warning system has been proposed (Japanese Laid Open Patent Application No.57-117096). In the vehicle's collision warning system, when a vehicle stands by for turn to the right at an intersection, it is determined whether a two-wheeled vehicle (e.g., a motorcycle) detected, by a roadside device, straightly passing through the intersection from the opposite side is in danger of being contact with the vehicle. Based on the determination result, a warning is issued in the vehicle. A driver of the vehicle standing by for turning to the right at the intersection actually ascertains the state of another vehicle from the opposite side by eyes and ascertains whether a warning is issued by the vehicle collision warning system. Thus, the driver can drive the vehicle to more securely turn to the right at the intersection.
Even if other vehicles are actually watched by a driver of a vehicle standing by for turning to the right at the intersection, the conventional vehicle's collision warning system as described above is activated for the other vehicles. Thus, although the driver drives the vehicle watching the other vehicles, a warning may be issued. In such a case, the warning may be officious for the driver.